Mobile water heating apparatus

ABSTRACT

A system for heating water used to produce hydraulic fracturing fluid (“fracing fluid”). The system includes a mobile water heating system, and first and second pumps. The heating system is configured to heat water at a first flow rate from a first temperature to a second temperature. The first pump pumps water having the first temperature from a water source to the heating system at the first flow rate. The second pump pumps the heated water from the heating system at a second flow rate. Both the first and second flow rates are at least 20 barrels per minute. The second pump pumps the heated water to a location (e.g., one or more tanks) whereat a proppant and/or a chemical may be added to the heated water to produce fracing fluid. The fracing fluid may be pumped to one or more wells and used to hydraulically fracture an underground formation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.13/689,654, filed on Nov. 29, 2012, which claims the benefit of U.S.Provisional Application No. 61/564,988, filed on Nov. 30, 2011, U.S.Provisional Application No. 61/613,449, filed on Mar. 20, 2012, U.S.Provisional Application No. 61/656,951, filed on Jun. 7, 2012, and U.S.Provisional Application No. 61/681,587, filed on Aug. 9, 2012, all ofwhich are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The following disclosure relates generally to water heaters, and moreparticularly to mobile water heaters having multiple burners andmultiple flame tubes or heating coils.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of a mobile water heating system havinga water heater configured in accordance with an embodiment of thepresent disclosure.

FIG. 2 is a partially schematic isometric view of the water heater ofFIG. 1.

FIG. 3 is a partially schematic, exploded, isometric view of the waterheater of FIG. 2 configured in accordance with an embodiment of thepresent disclosure.

FIG. 4A is a bottom view of a lid having a manifold configured inaccordance with an embodiment of the present disclosure.

FIGS. 4B and 4C are bottom views of lids having manifolds configured inaccordance with embodiments of the present disclosure.

FIG. 5 is a partially schematic, partial cross-sectional side view ofthe water heater of FIG. 3 configured in accordance with an embodimentof the present disclosure.

FIGS. 6 and 7 are partially schematic, partial cross-sectional sideviews of burner stacks configured in accordance with another embodimentof the present disclosure.

FIG. 8 is an isometric view of a vaporizer assembly configured inaccordance with another embodiment of the present disclosure.

FIG. 9 is a side view of a dual-coil vaporization coil configured inaccordance with another embodiment of the present disclosure.

FIG. 10 is a partially schematic, exploded isometric view of a lid, avent assembly, and a plurality of diffusers configured in accordancewith an embodiment of the present disclosure.

FIG. 11 is an isometric view of a diffuser configured in accordance withan embodiment of the present disclosure.

FIG. 12 is an isometric view of a heating coil configured in accordancewith an embodiment of the present disclosure.

FIG. 13 is a partially schematic, partially cutaway, cross-sectionalside view of a water heater configured in accordance with an embodimentof the present disclosure.

FIG. 14 is a schematic diagram of a water heating system configured inaccordance with an embodiment of the present disclosure.

FIG. 15 is a schematic of a fracing system that includes an embodimentof a mobile water heating system.

FIG. 16 is a schematic of an alternate embodiment of a mobile waterheating system for use with the fracing system of FIG. 15.

FIG. 17 is a schematic of another alternate embodiment of a mobile waterheating system for use with the fracing system of FIG. 15.

DETAILED DESCRIPTION

Direct contact water heaters can be used in industrial applications toheat large volumes of water for various applications. These waterheaters can come in various configurations and sizes that producevarying volumes of hot water. Generally, the larger the size of thewater heater, the larger the volume of hot water that can be produced.In many applications, water heaters are permanently installed in aparticular location, and the size of the water heater may not becritical. However, several industrial applications require hot water ina variety of locations that may change over a period of time. Forexample, drilling and/or mining operations are often conducted over alarge area or at different sites over a period of time. Theseapplications can require very large volumes of hot water, but cannotutilize a permanently installed and immobile large water heater.Adapting existing high volume direct contact water heaters to a mobileplatform is not practical because the size of the mobile platform wouldprevent its use on most roadways.

The following disclosure describes several embodiments of mobile directcontact water heaters having multiple burners and multiple flame tubes.Several of the embodiments described below include features oradvantages that overcome the limitations of existing water heaters.However, reference throughout this specification to features,advantages, or similar language does not imply that all of the featuresand advantages that may be realized with the present invention should beor are in any single embodiment of the invention. Rather, languagereferring to the features and advantages is understood to mean that aspecific feature, advantage, or characteristic described in connectionwith an embodiment is included in at least one embodiment of the presentinvention. Thus, discussion of the features and advantages, and similarlanguage, throughout this specification may, but do not necessarily,refer to the same embodiment.

Furthermore, the described features, advantages, and characteristics ofthe invention may be combined in any suitable manner in one or moreembodiments. One skilled in the relevant art will recognize that theinvention can be practiced without one or more of the specific featuresor advantages of a particular embodiment. In other instances, additionalfeatures and advantages may be recognized in certain embodiments thatmay not be present in all embodiments of the invention. Additionally, inthe following description of various embodiments of the presentinvention, numerous specific details are set forth in order to provide athorough understanding of embodiments of the present invention. In otherinstances, well-known components, methods, and procedures have not beendescribed so as not to unnecessarily obscure aspects of the embodimentsof the present invention.

The features and advantages of the present invention will become morefully apparent from the following description, or may be learned by thepractice of the invention as set forth hereinafter. In order that theadvantages of the invention will be readily understood, a description ofthe invention will be rendered by reference to specific embodiments thatare illustrated in the appended drawings. Understanding that thesedrawings depict only typical embodiments of the invention and are nottherefore to be considered to be limiting of its scope, the inventionwill be described and explained with reference to the accompanyingdrawings.

FIG. 1 is a side elevation view of a mobile water heating system 100having a water heater 102 configured in accordance with an embodiment ofthe present disclosure. In the illustrated embodiment, the water heater102 and a fuel tank 104 are operably attached to a ground vehicle, e.g.,a truck 107. The water heater 102 can include a first blower 106 a and asecond blower 106 b (not visible), identified collectively as theblowers 106. Although the illustrated embodiment includes two blowers106, other embodiments can include more or fewer blowers 106. The fueltank 104 can be configured to hold a variety of suitable fuels (e.g.,propane, natural gas, diesel fuel, etc.), and the water heater 102 canbe configured to burn a variety of suitable fuels. In the illustratedembodiment, the water heater 102 is configured to burn liquid propanegas (LPG) and the fuel tank 104 is configured to receive, store anddeliver LPG. However, in other embodiments, other fuels can be burned bythe water heater 102 and stored in the fuel tank 104. Accordingly, itshould be understood that reference to LPG throughout the presentdisclosure is illustrative of an embodiment of the disclosure, and thatother embodiments can utilize a variety of other suitable fuels.

As discussed above, larger direct contact water heaters generallyproduce larger volumes of hot water. Accordingly, for several highvolume applications requiring mobile hot water production, large mobilehot water heaters would be beneficial. However, in the United States,the maximum height allowed on roadways is regulated at the State level.The maximum vehicle height to ensure travel within all states is 4.1meters (13.5 feet). The maximum overall vehicle width permitted totravel on the National Network of highways is regulated at the Federallevel and is limited to 2.6 meters (102 inches). Accordingly, thedimensions of the heating system 100 and the water heater 102 must bewithin these limits to ensure travel on the National Network ofhighways. In the illustrated embodiment of FIG. 1, the heating system100 has an overall width less than 2.6 meters and an overall height H₁equal to 4.0 meters, and can thereby operate on roadways of all 50states. Several features of the water heater 102 provide for theproduction of large volumes of hot water within these size restrictions,as described in detail below.

FIG. 2 is a partially schematic isometric view of the water heater 102configured in accordance with an embodiment of the present disclosure.The water heater 102 in the illustrated embodiment is shaped as an ovalcylinder and includes a lid 202 having a plurality of exhaust vents 204.A pair of burner stacks 206 (identified individually as a first burnerstack 206 a and a second burner stack 206 b) are operably coupled to atopside of the lid 202. The lid 202 is removably coupled to a shell 210and a water inlet 208 extends through the lid 202. The perimeter of thelid 202 includes a flange 212 having a plurality of bolt holes (notshown). The shell 210 includes an upper flange 216 and a lower flange218. The upper flange 216 includes a plurality of bolt holes (not shown)that align with the bolt holes of the flange 212 on the lid 202. The lid202 can be removably coupled to the shell 210 by inserting bolts throughthe aligned bolt holes. The shell 210 is removably coupled to a waterreservoir 220 having a flange 222 via a plurality of aligned bolt holes(not shown) in the flange 222 and the lower flange 218.

FIG. 3 is a partially schematic, exploded, isometric view of the waterheater 102. In the illustrated embodiment, the water reservoir 220includes a plurality of slats 302 supporting a screen 304. A pair ofmetal rings 306 (identified individually as a first metal ring 306 a anda second metal ring 306 b) are fixedly attached to the slats 302 and/orthe screen 304. A first flame tube 308 a and a second flame tube 308 b(collectively the flame tubes 308) enclose the metal rings 306 a and 306b and extend from the screen 304 to a first cone 310 a and a second cone310 b (identified collectively as the cones 310), respectively. Thecones 310 encircle an upper portion of the flame tubes 308 and can atleast partially secure the flame tubes 308 in an upright position. Theflame tubes 308 can be constructed in a variety of suitable manners andfrom a variety of suitable materials. For example, the flame tubes 308of FIG. 3 include rolled metal mesh. In other embodiments the flametubes 308 can include rolled metal and/or other suitable materials. Thecones 310 a and 310 b can enclose a portion of the flame tubes 308 a and308 b and can be fixedly attached to an underside of the lid 202opposite the first burner stack 206 a and the second burner stack 206 b,respectively. A water manifold 312 includes the water inlet 208 and aplurality of water nozzles (not shown in FIG. 3). The water manifold 312can be operably coupled to the underside of the lid 202 and the inlet208 can extend through the lid 202 (as shown in FIG. 2).

In the illustrated embodiment, the oval-cylindrical shape of the waterheater 102 provides space within the shell 210 for the two flame tubes308 to be positioned side by side. In other embodiments, the waterheater 102 can be constructed in a variety of shapes and can haveadditional burner stacks 206 and flame tubes 308. For example, the waterheater 102 can be cylindrical, an elliptic cylinder, or can be arectangular cuboid and can contain three or more burner stacks 206 andcorresponding flame tubes 308. The shape of the water heater 102 and thenumber of flame tubes 308 and burner stacks 206 can be selected toincrease the thermal efficiency and capacity of the water heater 102.

FIG. 4A is a bottom view of the lid 202 having a manifold 402 configuredin accordance with an embodiment of the present disclosure. The manifold402 of the illustrated embodiment is similar in structure and functionto the manifold 312 discussed above with reference to FIG. 3 and can beused in place of the manifold 312. The manifold 402 is shaped similar toa figure-eight with two loops 404 a and 404 b encircling the cones 310 aand 310 b, respectively. A plurality of water outlets (e.g., holes) ornozzles 406 are installed in or on the water manifold 402 and positionedto encircle the cones 310. The lid 202 includes bolt holes 408positioned along the flange 212. The lid 202 can include anasymmetrically positioned bolt hole 407 that corresponds to anasymmetrically positioned bolt hole on the upper flange 216 of the shell210. The asymmetrically positioned bolt hole 407 can ensure the lid 202can only be removably coupled to the shell 210 in a particularorientation. The selected orientation can ensure components that areattached to the shell 210 or the lid 202 are correctly aligned forinterconnections with components attached to the truck 107 or otherparts of the mobile water heating system 100.

FIGS. 4B and 4C are bottom views of lids 202 having manifolds 412 and414, respectively, configured in accordance with additional embodimentsof the present disclosure. In the illustrated embodiments, the manifolds412, 414 include nozzles 406 positioned around the cones 310 a, 310 b ina manner at least generally similar to the manifolds 312 and 402. Thenozzles 406 can be positioned in a variety of suitable locations andarrangements. In the illustrated embodiments, for example, eachindividual nozzle 406 is spaced at least approximately equidistant fromthe nearest two nozzles 406.

FIG. 5 is a partially schematic, partial cross-sectional side view ofthe water heater 102 configured in accordance with an embodiment of thepresent disclosure. The shell 210 encloses an internal volume 502 thatincludes the flame tubes 308. The internal volume 502 can be at leastpartially filled with a heat transferring media 504. In the illustratedembodiment, the media 504 includes a plurality of pall rings 506. Inother embodiments, the heat transferring media 504 can include a varietyof other suitable material or devices (e.g., nutter rings, kings,P-rings, etc.) that encircle the flame tubes 308 and at least partiallyfill the internal volume 502. The screen 304 can have openings sized toprevent the media 504 from falling into the water reservoir 220. Theburner stacks 206 can include an air inlet duct 508, a fuel (e.g.,propane) inlet 510 and a burner 512 having a fuel vaporization coil 514and a fuel (e.g., propane) outlet (not shown in FIG. 5). The fuel inlet510 can be operably coupled to the fuel tank 104 (FIG. 1) and the inletduct 508 can be operably coupled to the blower 106 (FIG. 1) to providefuel and air, respectively, to the blower stacks 206.

FIGS. 6 and 7 are partially schematic, partial cross-sectional sideviews of one of the burner stacks 206 configured in accordance withanother embodiment of the present disclosure. In the illustratedembodiment, the burner stack 206 a includes two burners 512 (only oneburner 512 is visible in FIG. 7). In other embodiments, the burner stack206 a can include more or fewer burners (e.g., one burner 512, as shownin FIG. 5, or three or more burners 512). The burners 512 include fuel(e.g., propane) outlets 602, directed toward an interior portion of theburners 512. Air from the inlet duct 508 can enter the burner stack 206a and pass through and around the burners 512, as shown by the arrows inFIG. 7.

FIG. 8 is an isometric view of a vaporizer assembly 802 configured inaccordance with an embodiment of the present disclosure. In theillustrated embodiment, the vaporizer assembly 802 includes a length ofconduit or tubing identified as a vaporization coil 804 and a housing806. The vaporization coil 804 is positioned partially within thehousing 806 and includes a fuel (e.g., propane) inlet 808 and a fuel(e.g., propane) outlet 810. The housing 806 includes a generally flatsupport plate 807 fixedly attached to an upper portion of an annularbase 809. The vaporization coil 804 can be made from a metal or metalalloy tube that can be bent or shaped into the shape shown in FIG. 8.

In the illustrated embodiment, the vaporization coil 804 extends fromthe fuel inlet 808, under the base 809, and through a series of coils813 forming a cylinder within the base 809. The coils 813 can extendaround an internal surface of the annular base 809, with each successivecoil positioned on top of the preceding coil. From the coils 813, thevaporization coil 804 extends through a hole 811 in a sidewall portionof the base 809 to the fuel outlet 810. In one embodiment, the vaporizerassembly 802 can be positioned within a flame tube in a manner at leastgenerally similar to the vaporization coil 514 described above withrespect to FIG. 5. Although the illustrated embodiment of FIG. 8includes the housing 806 having an annular base 809 and the vaporizationcoil 804 having the series of coils 813, in other embodiments, thevaporizer assembly 802 can be configured in a variety of other suitablearrangements. For example, in one embodiment, the vaporizer assembly 802can be constructed without the housing 806. Additionally, the housing806 and/or the vaporization coil 804 can be shaped in a variety ofsuitable manners. For example, the coils 813 and the base 806 can beovoid, rectangular or square.

In some embodiments, a plurality of individual vaporization coils can beconnected to form a larger vaporization coil. FIG. 9, for example, is aside view of a dual-coil vaporization coil 902 having a firstvaporization coil 904 a and a second vaporization coil 904 b (identifiedcollectively as the vaporization coils 904). The vaporization coils 904can include fuel (e.g., propane) inlets 906 (identified individually asa first fuel inlet 906 a and a second fuel inlet 906 b) and fuel (e.g.,propane) outlets 908 (identified individually as a first fuel outlet 908a and a second fuel outlet 908 b). In one embodiment, the vaporizationcoils 904 can be connected together in series. For example, the fueloutlet 908 a of the first vaporization coil 904 a can be connected tothe fuel inlet 906 b of the second vaporization coil 904 b to superheatthe already vaporized fuel.

FIG. 10 is a partially schematic, exploded isometric view of a ventassembly 1002 and a plurality of vent covers or diffusers 1009 that canbe installed on the lid 202 in accordance with an embodiment of thepresent disclosure. The individual diffusers 1009 can be positioned inindividual exhaust vents 204 to reduce moisture loss and increaseefficiency of the water heater 102, as further described below. In theillustrated embodiment, the vent assembly 1002 includes a cover screen1006, a “C” shaped enclosure 1004 having an interior 1003, and a curvedcover plate 1008. The enclosure 1004 includes an inner wall 1010, anouter wall 1012, end walls 1014 and a plurality of mounting brackets1016 positioned along upper edge portions thereof. Dividers 1007 can bepositioned between the inner wall 1010 and the outer wall 1012. Thedividers 1007 can divide the vent assembly 1002 into several separateportions or sections and can provide structural support to the ventassembly 1002. The enclosure 1004 can be fixedly attached to the curvedcover plate 1008 by welding or another suitable method, and the coverscreen 1006 can be removably attached to the mounting brackets 1016 viafasteners through the brackets 1016. The vent assembly 1002 can beremovably attached to the lid 202 with the curved cover plate 1008covering several individual exhaust vents 204, and the remaining exhaustvents 204 being open to the interior 1003 of the enclosure 1004 throughindividual diffusers 1009. The interior 1003 can be filled with a media(not shown), e.g., pall rings, to trap free moisture from the exhaustthat is not removed by the diffusers 1009.

Although the illustrated embodiment of FIG. 10 includes a vent assembly1002 having an enclosure 1004 that is divided into multiple sections bythe dividers 1007, in other embodiments, the enclosure 1004 can beconstructed without dividers and include an undivided interior 1003.Furthermore, in some embodiments, the vent assembly 1002 can includeseveral independent enclosures that can each be individually attached tothe lid 202. For example, in some embodiments two or more individualenclosures can be attached to the lid 202 at different locations tocollect and trap free moisture from the exhaust.

The illustrated embodiment of FIG. 10 includes a pair of high-efficiencyburners 1016 (identified individually as a first burner 1016 a and asecond burner 1016 b), shown schematically. The burners 1016 can beoperably coupled to the lid 202 and/or the vaporizer assembly 802 ofFIG. 8. In one embodiment, the burners 1016 can be Ovenpak IndustrialBurners, produced by Maxon Corp. High-efficiency burners, such asOvenpak Industrial Burners can be designed to operate at an optimumefficiency on low pressure gas. In some embodiments, the burners 1016can include a self-contained blower that operates in conjunction with,or independent of, the blowers 106. The burners 1016 can be operablycoupled to the fuel outlet 810 of the vaporizer assembly 802 of FIG. 8and/or to the fuel outlets 908 of the vaporization coil 902 of FIG. 9.In operation, the vaporizer assembly 802 and/or the vaporization coil902 can convert the LPG from the fuel tank 104 (FIG. 1) to gaseouspropane, which is delivered to the burners 1016 for efficient burning,as will be further described below.

FIG. 11 is an isometric view of an individual diffuser 1009 configuredin accordance with an embodiment of the present disclosure. In theillustrated embodiment, the diffuser 1009 includes a frame 1102 and aplurality of slats 1104. The slats 1104 can be fixedly attached to theframe 1102 with the slats 1104 positioned at an angle to horizontal.Additionally, the slats 1104 can be positioned in an offset pattern, asshown in FIG. 11. The angled slats 1104 and the offset pattern cancreate a labyrinth path for air that exits through the diffuser 1009.The labyrinth path can aid in removing free moisture from an exhaustflow, and thereby increase the efficiency of the water heater byreducing the emission of heated water vapor.

FIGS. 1-11 illustrate several components and features of the mobilewater heating system 100. However, several additional components orfeatures have not been illustrated so as not to obscure the illustratedembodiments. For example, the heating system 100 can include an electricgenerator to provide power for various components. Additionally, pumps,pipes, hoses, valves, and various other suitable components can beincluded in the mobile water heating system 100 to facilitate itsoperation. A filtration system can be included to remove impurities orother material from water prior to introducing the water into the waterheater 102. A control panel, control circuits, switches, level sensors,and various other suitable electric or electromechanical devices can beincluded in the mobile water heating system 100 to control the operationof various components or automate operations of the water heater 102 orother components.

In operation, the water heater 102 can burn LPG from the fuel tank 104to heat water from a water source (e.g., a water source 1510 illustratedin FIG. 15). Referring to FIGS. 1-11 together, a hose or series of hosescan be connected to the water heating system 100 and a pump can pumpwater from the water source (e.g., the water source 1510 illustrated inFIG. 15) to the water inlet 208. LPG from the fuel tank 104 can bedirected to the fuel inlets 510 of the burners 512 and the blowers 106can blow air into the burner stacks 206 through the inlet duct 508. TheLPG and the air can mix within the burners 512 to form a combustiblemixture. An igniter (not shown) can ignite the combustible mixture,creating flames that extend through the cones 310 and into the flametubes 308. The flames and combustion gases heat the vaporization coils514 causing the LPG to vaporize (e.g., transforming the LPG from aliquid fuel to a gaseous fuel) and providing a more efficient burningprocess.

In embodiments having high efficiency burners, such as the burners 1016of FIG. 10, the LPG can be directed from the fuel tank 104 to one ormore of the vaporizer assemblies 802 (FIG. 8) or vaporizer coils 902(FIG. 9) via the fuel inlets 808 or 906. Similar to the operationdescribed above, all or a portion of the LPG can be vaporized invaporization coils 804 or 904 and delivered to the burners 1016 forefficient burning. The burners 512 or 1016 and air from the blowers 106or the self contained blowers direct the flames and combustion gasesdownwardly through the flame tubes 308 heating the flame tubes 308 andthe pall rings 506 surrounding the flame tubes 308. The cones 310 reducethe area of the lid 202 directly exposed to heat from within the flametubes 308. This reduced exposure of the lid 202 to direct heating canreduce undesirable overheating of the lid 202.

In embodiments having flame tubes 308 constructed from rolled metal orother solid material, the combustion gases exit the lower end of theflame tubes 308 and pass into the water reservoir 220. The combustiongases then rise through the shell 210, further heating the pall rings506 and the flame tubes 308, and then exit through the exhaust vents204. In embodiments having wire mesh flame tubes 308, the combustiongases can also pass through the wire mesh along the length of the flametubes 308 and proceed through the pall rings 506. As discussed above,the diffusers 1009 can be positioned in the exhaust vents 204. Thediffusers 1009 can reduce the amount of free moisture that is carried bythe exhaust out of the shell 210, thereby increasing the efficiency ofthe mobile water heating system 100. Additionally, the vent assembly1002 can further reduce the amount of free moisture carried by theexhaust. In embodiments having the vent assembly 1002, the exhaust exitsthe shell 210 through the diffusers 1009 and enters the interior 1003 ofthe enclosure 1004. The exhaust passes through the media (e.g., pallrings) within the enclosure 1004 and exits through the cover screen1006. As the exhaust passes through the enclosure 1004, moisture in theexhaust condenses on the media and returns to the shell 210 through theexhaust vents 204 and/or the diffusers 1009. The removal of thisadditional moisture from the exhaust further increases the efficiency ofthe mobile water heating system 100.

The pumped water enters the manifold 312, 402, 412 or 414 through theinlet 208 and is sprayed out of the nozzles 406. The water is sprayedonto the heated pall rings 506 and/or the flame tubes 308 and heat fromthe pall rings 506 and/or the flame tubes 308 is transferred to thewater. In some embodiments, the water can be sprayed onto the pall rings506 without being sprayed directly onto the flame tubes 308. Forexample, in some embodiments the nozzles 406 can be positioned and/orshaped to direct a spray pattern of water onto the pall rings 506without spraying water directly onto the flame tubes 308. In otherembodiments, the nozzles 406 can be positioned and/or shaped to spraywater directly onto the pall rings 506 and directly onto the flame tubes308. In yet other embodiments, the nozzles 406 can be positioned and/orshaped to spray water directly onto the flame tubes 308 without sprayingwater directly onto the pall rings 506. The heated water travelsdownwardly through the shell 210 under the force of gravity and canundergo further heating through additional contact with the heated pallrings 506 and/or the flame tubes 308. Additionally, the combustion gasesand/or the flames can provide direct heating of the water as the watertravels through the shell 210. Without wishing to be bound by theory, itis believed that in some embodiments the pall rings 506 can act to slowand disperse the water as it passes through the shell 210, therebyproviding increased heating of the water by the combustion gases and/orthe flames. The heated water passes through the shell 210 and fallsthrough openings in the screen 304 into the water reservoir 220. Theflame and combustion gases from the flame tubes 308 are directeddownwardly into contact with the heated water in the reservoir 220,providing additional heating. The heated water in the reservoir 220 canbe dispensed or pumped through an outlet 1526 (see FIG. 15) and directedthrough a series of hoses or pipes to a desired location.

FIG. 12 is an isometric view of a flame director or heating coil 1200configured in accordance with an embodiment of the present disclosure.The heating coil 1200 can direct flame and combustion gases through theshell of a water heater in a manner at least generally similar to thatdescribed above with respect to the flame tubes 308, as will be furtherdescribed below. In the illustrated embodiment, the heating coil 1200includes a metal or metal alloy tube 1202 that can be rolled, bent orotherwise formed into the coiled tubular or cylindrical shapeillustrated in FIG. 12. Water can be flowed or directed into an inlet1204 at an upper end 1203 of the heating coil 1200. For example, in oneembodiment, in addition to directing water to the manifold 302, 402, 412or 414, the water inlet 208 (FIGS. 2 and 3) can include one or morejunctions or outlets that can provide water to one or more heating coils1200. In some embodiments, the manifolds 302, 402, 412 or 414 caninclude one or more junctions or outlets positioned at other locationsand configured to direct water to one or more heating coils 1200. Inoperation, water flows into the inlet 1204, through the heating coil1200, and exits through an outlet 1206 at a lower end 1205 of theheating coil 1200. A shroud 1210 can be positioned (e.g., welded) at theupper end 1203 of the heating coil 1200. The shroud 1210 can aid inproviding a uniform fit between the heating coil 1200 and an individualcone 310 (FIGS. 3-4C). In operation, flame and combustion gases directedthrough the heating coil 1200 can heat the metal tube 1202, causingexpansion of the metal tube 1202. A plurality of individual weld jointsor welds 1208 connecting adjoining portions of the metal tube 1202,however, can reduce expansion of the heating coil 1200 caused by theheating.

FIG. 13 is a partially schematic, partially cutaway, cross-sectionalside view of a water heater 1302 configured in accordance with anembodiment of the present disclosure. In the illustrated embodiment, thewater heater 1302 includes two heating coils 1200 (only one visible inFIG. 13). Vaporization coils 1304 (only one visible in FIG. 13), eachhaving an inlet 1306 and an outlet 1308, can be positioned within theupper portion 1203 of each of the heating coils 1200 and operablycoupled to provide propane to individual burners 1016 a, 1016 b (burner1016 b not visible in FIG. 13) via the outlets 1308.

The water heater 1302 can operate in a manner at least generally similarto the water heater 102 described above. For example, LPG can bedirected to the inlets 1306 of the vaporization coils 1304. The LPG canbe converted to gaseous propane within the vaporization coils 1304 anddirected through the outlets 1308 to the burners 1016. The burners 1016can burn the gaseous propane and direct the flame and resultingcombustion gases downwardly through the heating coils 1200. Water can bedirected to the manifold 412 and through the tubes 1202 of the heatingcoils 1200, as described above. The flame and the combustion gases canheat the heating coils 1200, resulting in heating of the water travelingthrough the heating coils 1200. The heated water can exit the heatingcoils 1200 through the outlets 1206 and be directed into the waterreservoir 220. The water traveling through the heating coils 1200 cancool the heating coils 1200. Additionally, water from the manifold 412can be sprayed from the nozzles 406 and travel downwardly through thepall rings 506. The nozzles 406 can be positioned to direct the wateruniformly, or at least approximately uniformly, over the top of the pallrings 506. In the illustrated embodiment, the nozzles 406 are positionedto direct a spray pattern of water onto the pall rings 506 withoutspraying water directly onto the heating coils 1200. In otherembodiments, the nozzles 406 can be positioned to spray water onto thepall rings 506 and the heating coils 1200, or just onto the heatingcoils 1200. The combustion gases and heated air can exit the lower end1205 of the heating coils 1200 and travel upwardly, heating the watertraveling downwardly through the pall rings 506. Accordingly, the waterin the reservoir 220 can include water that has been heated as ittravels through the tubes 1202 of the heating coils 1200, as well aswater that has been heated as it travels downwardly through the pallrings 506. Furthermore, the flame and the combustion gases can bedirected downwardly through the heating coils 1200 into the waterreservoir 220, further heating the water in the water reservoir 220.Although the term “heating coil” is used herein to refer to the heatingcoils 1200, flame directors in accordance with the present technology,including the heating coils 1200, can also be referred to as flametubes.

A variety of control systems, computers, electrical devices, mechanicaldevices, electromechanical devices, and other suitable components can beemployed in embodiments in accordance with the present technology. Inseveral embodiments combinations of engines, generators, pumps, motors,valves, solenoids, sensors, electronic control circuits, controllers,converters, drivers, logic circuitry, control panels, displays,input/output (I/O) interfaces, connectors or ports, personal computers(PCs), computer readable media, software, and/or other components areoperably connected to the water heater 102 to control or engage invarious operations. For example, FIG. 14 is a schematic diagram of awater heating system 1400 having various components configured tocontrol the water heater 102 in accordance with an embodiment of thepresent technology. In the illustrated embodiment, an engine 1402 isoperably coupled to a hydraulic pump 1404. In one embodiment, the engine1402 can be a main engine, e.g., an internal combustion engine, of thetruck 107 (FIG. 1). The hydraulic pump 1404 can be operably coupled to ahydraulically driven generator 1406 to produce electrical power. Thegenerator 1406 can be electrically coupled to a power distributionsystem 1408 that can distribute the electrical power to variouscomponents that operate or control the water heater 102.

A controller, e.g., a programmable logic controller 1410, can be coupledto a variety of components to control the operations of the water heater102. For example, in the illustrated embodiment, the controller 1410receives power from the distribution system 1408 and is electricallycoupled to: the blowers 106 (second blower 106 b not visible); theburners 1016 (second burner 1016 b not visible); an inlet pump or firstpump 1416 a and an outlet pump or second pump 1416 b (collectively, thepumps 1416); a pneumatic water inlet valve 1418; a pneumatic wateroutlet valve 1417; a pneumatic trim valve 1419; a water level sensor1422; pneumatic pilot valves 1428 (only one visible in FIG. 14);pneumatic mid-burn valves 1429 (only one visible in FIG. 14); pneumaticfull-burn valves 1431 (only one visible in FIG. 14); a fuel pump 1426;an air system 1414; and a first control panel 1412 a and a secondcontrol panel 1412 b (collectively, the control panels 1412). Thecontroller 1410 and/or other components of the water heating system 1400can include ports that can connect the controller 1410 to additionalcomponents, such as a host computer or PC to install or update softwareor can allow connections for operations such as field service ordebugging. The controller 1410 can include memory, e.g., random accessmemory (RAM), read-only memory, and/or non-volatile random access memory(NVRAM). The memory can store software and data that can be executed orutilized by the controller to control various operations of the waterheating system 1400.

The power distribution system 1408 can provide power to components ofthe water heating system 1400, including components that areelectrically coupled to the controller 1410, as illustrated in FIG. 14.The air system 1414 can include an air compressor and an air tank toprovide air to operate the pneumatic valves 1417-1419, 1428, 1429 and1431 and/or to provide air for blowing down hoses, pipes and/or othercomponents of the water heating system 1400. Embodiments in accordancewith the present technology can include components positioned in avariety of suitable locations. For example, in one embodiment, the firstcontrol panel 1412 a can be located in a cab of the truck 107 (FIG. 1)and the second control panel 1412 b can be located proximate to the fueltank 104. The control panels 1412 can include various user input devicesfor operation of the water heater 102 in a manual mode, in an automaticmode, and/or in other modes of operation (e.g., test modes). Thecontroller 1410 and several of the components of the embodiment shown inFIG. 14 are schematically illustrated as being physically isolated fromother components. However, it is to be understood that the controller1410 and other components of the water heating system 1400 can becoupled to, integral with, or otherwise associated with a variety ofother components or parts of the water heating system 1400 and/or of anyground vehicle to which the water heating system 1400 is operablycoupled. For example, in one embodiment, the water heating system 1400can include additional controllers 1400 that are integral with theburners 1016.

In operation, an operator can control the water heater 102 via either ofthe control panels 1412. The control panels 1412 can graphically displaythe condition of various components and/or of various operatingparameters, e.g., pump status (on or off), valve status (open, closed,or trim position), burner status (off, pilot, mid-burn, or full-burn),inlet water temperature, outlet water temperature, temperaturedifference (e.g., outlet temperature minus inlet temperature), and flowrate (barrels of water per minute). The operator can start the engine1402 and engage the hydraulic pump 1404 to provide power to the powerdistribution system 1408 and the air system 1414. The inlet pump 1416 acan be coupled to a water source 1420 via hoses 1434 and a filter 1432.The filter 1432 can remove debris and/or contamination from the water toimprove the efficiency and operation of the water heater 102. In oneembodiment, the operator can open the inlet valve 1418 and start theinlet pump 1416 a in the manual mode of operation. The inlet pump 1416 apumps water into the water heater 102 and the control panel indicates arising water level via signals from the water level sensor 1422. Whenthe water level reaches a predetermined level, the operator can put thesystem into automatic water level control and the controller 1410 canmaintain the water level within a suitable range. For example, inautomatic mode, the controller 1410 can open the outlet valve 1417,start the outlet pump 1416 b and adjust the position of the trim valve1419 to direct water out the discharge outlet 1430. When the water leveldrops below a predetermined lower limit, the controller 1410 canposition the trim valve 1419 to restrict the flow, and when the waterlevel rises above a predetermined upper limit, the controller 1410 canposition the trim valve 1419 in a fully open position to increase theoutflow.

A variety of suitable parameters can be used to initiate automaticshutdowns and/or other functions to provide safe operation or othercontrol features. For example, in one embodiment, the level sensor 1422can provide a signal to temporarily shut down the water heater 102 inthe event the water level rises above a predetermined limit, or fallsbelow a predetermined limit. In some embodiments, the burners 1016and/or the controller 1410 can include computer readable instructionsthat instruct a delayed opening of the fuel valves and/or delays ofother ignition sequence events until a predetermined amount of time haspassed. For example, in one embodiment, the burners 1016 delay ignitionuntil the blowers 106 have operated for at least 30 seconds to purge anycombustible gases within the shell 210. The blowers 106 can providevarious amounts of airflow during the purging of the shell 210. In oneembodiment, the blowers 210 provide 3400 cubic feet per minute ofairflow during purging.

An ignition sequence for the water heating system 1400 can includeopening of the pilot valves 1428 and operation of igniters within theburners 1016. The burners 1016 can include sensors to determine if anignition was successful, and if so, a signal can be sent to open themid-burn valves 1429. Fuel flow through the mid-burn valves 1429 canproduce sufficient flames to heat the vaporization coils 1304 (FIG. 12),and in many instances provides sufficient heat to maintain or achieve adesired output water temperature. After a predetermined time ofoperation with the mid-burn valves 1429 open, the full-burn valves 1431can be opened to provide fuel to the vaporization coils via thevaporization coil inlets 1306 (only one visible in FIG. 14). The fuelpump 1426 can provide increased fuel flow to the burners 1016. Forexample, during operation in cold temperatures, fuel flow from the fueltank 104 may be inadequate to provide sufficient liquid fuel to thevaporization coils 1304. The fuel pump 1426 can be activated via thecontroller 1410 to pump additional liquid fuel. In some embodiments,activation of the fuel pump 1426 is controlled manually via the controlpanels 1412.

The water heater 102 and the associated components illustrated in theFigures are illustrative of several embodiments of the presenttechnology. In other embodiments, additional and/or fewer components canbe included in a variety of suitable configurations. Additionally, inorder to not obscure the present technology, well-known components areomitted and/or not set forth in detail in the Figures. For example,several embodiments can include regulators, pressure sensors, flowmeters, switches, additional fuel valves, and/or other components.

Without being bound by any particular theory, it is believed that themultiple flame tubes 308, multiple heating coils 1200, multiple burners512 and/or the oval-cylindrical shape of the water heaters 102, 1302provide for a more efficient heating of the water. These features, aloneor in combination with other features, can provide large volume hotwater production in a mobile design of a size that permits transport onmost roads. Accordingly, hot water heaters configured in accordance withthe embodiments of the present disclosure can provide large volumemobile hot water production that can be used in a variety of suitableapplications. Additionally, the heating coils 1200 described above canprovide for lower noise generation when compared to heating systems ofother designs. Again, without being bound by theory, it is believed thatthe shape of the heating coils 1200 can reduce noise production byproviding multiple surfaces of varying angles for sound to reflect from.For example, the coiled tubular shape of the heating coil 1200 includesmultiple coils of the metal tube 1202, each of which provides surfacesthat can reflect the sound generated by the burners 1016.

Furthermore, existing heating solutions typically provide watertemperature increases of 50-60 degrees Fahrenheit and water flow ofapproximately 250 gallons per minute. Several embodiments in accordancewith the present technology can produce water temperature increases offrom about 75 degrees to about 85 degrees Fahrenheit, with flow rates ofabout 450 gallons per minute. For example, in one embodiment, the waterheater 102 can heat water from an inlet temperature of 40 degreesFahrenheit to an outlet temperature of 125 degrees Fahrenheit with aflow rate of 450 gallons per minute. In other embodiments, higher orlower flow rates or ranges of temperature increases can be achieved,depending on the design characteristics of the particular embodiment.Additionally, existing water heating solutions often employ open heatingchambers that utilize closed flow-through pipes to heat water. The openheat chambers can produce large amounts of heat and present asignificant fire hazard. Embodiments in accordance with the presenttechnology can heat water within an internal volume of a shell that isbathed in water. This can reduce the risk of fires and providesignificant advantages in locations that may present fire dangers (e.g.,oil and gas exploration or drilling sites).

FIG. 15 is a schematic of a fracing system 1500 that includes a mobilewater heating system 1502. The heating system 1502 may be implementedusing the mobile water heating system 100 (see FIG. 1) or the waterheating system 1400 (see FIG. 14). The heating system 1502 is configuredto receive and heat all of the water used to produce fracing fluid forhydraulically fracturing one or more wells (e.g., a well 1560). In theembodiment illustrated, the heating system 1502 includes the waterheater 1302 depicted in FIG. 13. However, any of the direct contactwater heaters described herein may be used. Each of the water manifolds312, 402, 412, and 414 may be configured to provide sufficient flowrates therethrough. For ease of illustration, some of the components ofthe water heater 1302 have been omitted from FIG. 15.

By way of a non-limiting example, the heating system 1502 may beconfigured to receive and heat about 20 barrels (of water) per minute ormore. At this flow rate, the heating system 1502 may increase thetemperature of the water by about 40 degrees to about 50 degreesFahrenheit. Thus, if the heating system 1502 receives water having atemperature of about 40 degrees Fahrenheit, the heating system 1502 mayheat the water to a temperature of about 90 degrees Fahrenheit at a flowrate of at least 20 barrels per minute. Higher or lower flow rates ordifferent ranges of temperature increase may be achieved depending onthe design characteristics of the particular embodiment. By way ofanother non-limiting example, the heating system 1502 may be configuredto heat at least about 100 barrels of water per minute. By way ofanother non-limiting example, the heating system 1502 may be configuredto increase the temperature of the water by as little as about 8 degreesFahrenheit to about 10 degrees Fahrenheit. In alternate embodiments suchas those depicted in FIGS. 16 and 17 (described below), multiple waterheaters may be used to achieve larger temperature increases.

Referring to FIG. 15, the mobile water heating system 1502 may includeinlet and outlet pumps 1520 and 1530. In embodiments in which the mobilewater heating system 1502 is implemented using the mobile water heatingsystem 1400, the inlet and outlet pumps 1520 and 1530 may beincorporated into the water heating system 1400 (see FIG. 14) in placeof the inlet and outlet pumps 1416 a and 1416 b (see FIG. 14). Each ofthe inlet and outlet pumps 1520 and 1530 may be implemented by a singlepump or multiple pumps working together. Each of the inlet and outletpumps 1520 and 1530 may be mounted on a truck and/or a trailer that istransportable separately from other components of the mobile waterheating system 1502. Alternatively, one or more of the inlet and outletpumps 1520 and 1530 may be operably attached to the truck 107 (seeFIG. 1) and/or a trailer pulled thereby. Each of the inlet and outletpumps 1520 and 1530 may be configured to pump water or fracing fluid atrates of 20 barrels per minute or more. By way of another non-limitingexample, each of the inlet and outlet pumps 1520 and 1530 may beconfigured to pump water or fracing fluid at a rate of at least about100 barrels per minute.

The fracing system 1500 obtains water from the water source 1510, whichmay be a ground water well, a river, a stream, a lake, a tank, a pond,and the like. Water is pumped from the water source 1510 by the inletpump 1520 via a first flowline 1522. The water pumped from the watersource 1510 is pumped via a second flowline 1524 to at least one waterinlet 1528 (which may be substantially similar to the water inlet 208illustrated in FIG. 3) of the manifold 412 of the water heater 1302.

Referring to FIG. 13, water exits the manifold 412 through the tubes1202 of the pair of heating coils 1200 as well as through the nozzles406. This water is heated as described above and collects in the waterreservoir 220. Furthermore, as described above, additional heat may beadded to the heated water in the water reservoir 220.

At least a portion of the heated water is pumped by the outlet pump 1530from the water reservoir 220 via the water outlet 1526 and a thirdflowline 1532. In alternate embodiments, the water reservoir 220 mayinclude multiple water outlets through which the outlet pump 1530 maypump the heated water via one or more flowlines.

The heated water pumped from the water reservoir 220 is pumped by theoutlet pump 1530 to a location whereat proppants, chemicals, and/orother substances may be added to the heated water to produce fracingfluid. By way of an example, the outlet pump 1530 may pump the heatedwater to one or more mixing tanks (e.g., a mixing tank 1540) via afourth flowline 1534. One or more proppants, chemicals, and/or othersubstances may be added to the heated water in the mixing tank(s) 1540to produce the fracing fluid. For ease of illustration, the locationwill be described as being the mixing tank 1540. However, this is not arequirement. Alternate structures other than one or more mixing tanksmay be used to add one or more proppants, one or more chemicals, and/orother substances to the heated water to produce fracing fluid.

The fracing fluid is pumped from the mixing tank(s) 1540 by a pump 1550via a fifth flowline 1542. The fracing fluid pumped from the mixingtank(s) 1540 is pumped by the pump 1550 to one or more wells (e.g., thewell 1560) via one or more flowlines (e.g., a sixth flowline 1552). Atthe well 1560, the fracing fluid is pumped downhole and used tohydraulically fracture an underground formation. The hydraulicfracturing may cause the well 1560 to produce oil, gas, a combinationthereof, or the like.

In the system 1500, none of the water pumped from the water source 1510bypasses the heating system 1502 and travels directly to the well 1560or the mixing tank(s) 1540. Further, none of the water heated by theheating system 1502 is mixed with unheated water pumped from the watersource 1510. Instead, all of the water used to produce the fracing fluidis heated by the heating system 1502.

Each of the flowlines 1522, 1524, 1532, 1534, 1542, and 1552 may beimplemented using any pipe or conduit suitable for transporting water orfracing fluid at a hydraulic fracturing job site. By way of anon-limiting example, one or more of the flowlines 1522, 1524, 1532,1534, 1542, and 1552 may have a diameter of approximately 12 inches.Further, each of the flowlines 1522, 1524, 1532, 1534, 1542, and 1552may be implemented using one or more separate flowlines.

FIG. 16 is a schematic of a mobile water heating system 1600 that is analternate embodiment of the heating system 1502 illustrated in FIG. 15.The mobile water heating system 1600 may be operably attached to thetruck 107 (see FIG. 1) and/or a trailer pulled thereby. Like referencenumerals have been used to identify like components in FIGS. 15 and 16.The mobile water heating system 1600 may be substituted for the mobilewater heating system 1502 in FIG. 15. In such embodiments, none of thewater pumped from the water source 1510 bypasses the heating system 1600and travels directly to the well 1560 or the mixing tank(s) 1540.Further, none of the water heated by the heating system 1600 is mixedwith unheated water pumped from the water source 1510. Instead, all ofthe water used to produce the fracing fluid is heated by the heatingsystem 1600.

Instead of including a single water heater, the heating system 1600includes a plurality of water heaters. In the embodiment illustrated,the heating system 1600 includes a first water heater 1601 and a secondwater heater 1602. However, any number of water heaters may be used. Byway of a non-limiting example, the heating system 1600 may include two,three, or four water heaters. For ease of illustration, some of thecomponents of the water heaters 1601 and 1602 have been omitted fromFIG. 16. Each of the first and second water heaters 1601 and 1602 may beimplemented using the water heater 1302 modified to supply heated waterto a common or shared water reservoir 1610. Alternatively, any of thedirect contact water heaters described herein may be used to supplyheated water to the shared water reservoir 1610. Further, the waterheaters of the heating system 1600 need not be implemented bysubstantially identical direct contact water heaters.

The inlet pump 1520 (see FIG. 15) may pump water from the water source1510 (see FIG. 15) to the heating system 1600 via the second flowline1524. However, in this embodiment, the second flowline 1524 is modifiedto supply water to each of the plurality of water heaters (e.g., thefirst and second water heaters 1601 and 1602). At least a portion of theheated water is pumped by the outlet pump 1530 (see FIG. 15) from thewater reservoir 1610 via the water outlet 1526 and the third flowline1532. In alternate embodiments, the water reservoir 1610 may includemultiple water outlets through which the outlet pump 1530 may pump theheated water via one or more flowlines.

Because each of the plurality of water heaters of the heating system1600 heats only a portion of the water pumped to the heating system 1600by the inlet pump 1520, the heating system 1600 may increase thetemperature of the water by a greater amount than the heating system1502. For example, if the water heaters 1302, 1601, and 1602 aresubstantially identical to one another, and the water heater 1302 of theheating system 1502 is configured to heat 20 barrels per minute by 40degrees Fahrenheit, the first and second water heaters 1601 and 1602 mayeach heat 10 barrels per minute by 80 degrees Fahrenheit. Thus, in thisexample, the heating system 1502 will output water that is about 40degrees Fahrenheit cooler than the water heated by the heating system1600. The amount of temperature increase that may be accomplished by theheating system 1600 may be determined at least in part by the number ofwater heaters included in the heating system 1600.

FIG. 17 is a schematic of a mobile water heating system 1700 that isanother alternate embodiment of the heating system 1502 illustrated inFIG. 15. The mobile water heating system 1700 may be operably attachedto the truck 107 (see FIG. 1) and/or a trailer pulled thereby. Likereference numerals have been used to identify like components in FIGS.15 and 17. The heating system 1700 may be substituted for the heatingsystem 1502 in FIG. 15. In such embodiments, none of the water pumpedfrom the water source 1510 bypasses the heating system 1700 and travelsdirectly to the well 1560 or the mixing tank(s) 1540. Further, none ofthe water heated by the heating system 1700 is mixed with unheated waterpumped from the water source 1510. Instead, all of the water used toproduce the fracing fluid is heated by the heating system 1700.

Instead of including a single water heater, the heating system 1700includes a plurality of water heaters connected together in series. Inthe embodiment illustrated, the heating system 1700 includes a firstwater heater 1701 and a second water heater 1702. However, any number ofwater heaters may be used. By way of a non-limiting example, the heatingsystem 1600 may include two, three, or four water heaters. For ease ofillustration, some of the components of the water heaters 1701 and 1702have been omitted from FIG. 17. Each of the first and second waterheaters 1701 and 1702 may be implemented using the water heater 1302 orany of the direct contact water heaters described herein. Further, thewater heaters of the heating system 1700 need not be implemented bysubstantially identical direct contact water heaters.

The inlet pump 1520 (see FIG. 15) may pump water from the water source1510 (see FIG. 15) to the at least one water inlet 1528 of the manifold412 of the first water heater 1701 via the second flowline 1524. Heatedwater collects in the water reservoir 220 of the first water heater1701.

A pump 1720 pumps heated water from the water reservoir 220 of the firstwater heater 1701 via a seventh flowline 1730. Then, the pump 1720 pumpsthe heated water to at least one water inlet 1728 of the manifold 412 ofthe second water heater 1702 via an eighth flowline 1732. Heated watercollects in the water reservoir 220 of the second water heater 1702.

At least a portion of the heated water is pumped by the outlet pump 1530(see FIG. 15) from the water reservoir 220 of the second water heater1702 via the water outlet 1526 and the third flowline 1532. In alternateembodiments, the water reservoir 220 of the second water heater 1702 mayinclude multiple water outlets through which the outlet pump 1530 maypump the heated water via one or more flowlines.

Because each of the plurality of water heaters of the heating system1700 heats the water serially, the heating system 1700 may increase thetemperature of the water by a greater amount than the heating system1502. For example, if the water heaters 1302, 1701, and 1702 aresubstantially identical to one another, and the water heater 1302 of theheating system 1502 is configured to heat 20 barrels per minute by 40degrees Fahrenheit, together the first and second water heaters 1701 and1702 heat 20 barrels per minute by 80 degrees Fahrenheit. Thus, in thisexample, the heating system 1502 will output water that is about 40degrees Fahrenheit cooler than the water heated by the heating system1700. Therefore, the amount of temperature increase accomplished by theheating system 1700 may be determined at least in part by the number ofwater heaters connected together in series in the heating system 1700.From the foregoing, it will be appreciated that specific embodiments ofthe invention have been described herein for purposes of illustration,but that various modifications may be made without deviating from thespirit and scope of the various embodiments of the invention. Forexample, the water heaters disclosed herein can be constructed invarious shapes and sizes, and can include differing numbers of flametubes, heating coils and burners. Additionally, any of the embodimentsshown or described herein may be combined with each other as the contextpermits. Accordingly, the invention is not limited except as by theappended claims.

The invention claimed is:
 1. A method for use with a water source, themethod comprising: pumping, with at least one first pump, water having afirst temperature from the water source to a mobile water heating systemat a first flow rate of at least 20 barrels per minute; heating, withthe mobile water heating system, the water pumped to the mobile waterheating system to a second temperature greater than the firsttemperature; and pumping, with at least one second pump, the heatedwater from the mobile water heating system at a second flow rate of atleast 20 barrels per minute to a location whereat at least one of aproppant and a chemical are added to the heated water to produce fracingfluid.
 2. The method of claim 1, wherein the location is at least onetank.
 3. The method of claim 1, wherein the mobile water heating systemcomprises a water reservoir in which water heated to the secondtemperature collects, and the at least one second pump pumps heatedwater from the water reservoir at the second flow rate.
 4. The method ofclaim 1, wherein the second temperature is at least 8 degrees Fahrenheitgreater than the first temperature.
 5. The method of claim 1, whereinthe first and second flow rates are each at least 100 barrels perminute.
 6. The method of claim 1, wherein the second temperature is atleast 8 degrees Fahrenheit greater than the first temperature, and thefirst and second flow rates are each at least 100 barrels per minute. 7.The method of claim 1, wherein the mobile water heating system comprisesa first truck, and the at least one first pump is transported by asecond truck that is different from the first truck.
 8. The method ofclaim 1, wherein the mobile water heating system comprises a firsttruck, the at least one first pump is a first single pump transported bya second truck that is different from the first truck, and the at leastone second pump is a second single pump transported by a third truckthat is different from the first and second trucks.
 9. The method ofclaim 1, wherein the mobile water heating system comprises a firsttruck, and the at least one second pump is transported by a second truckthat is different from the first truck.
 10. A system for use with awater source and at least one tank, the system comprising: a mobilewater heating system configured to heat water at a first flow rate of atleast 20 barrels per minute from a first temperature to a secondtemperature that is greater than the first temperature; at least onefirst pump configured to pump water having the first temperature fromthe water source to the mobile water heating system at the first flowrate; and at least one second pump configured to pump the heated waterat a second flow rate of at least 20 barrels per minute from the mobilewater heating system to the at least one tank whereat at least one of aproppant and a chemical are added to the heated water to produce fracingfluid.
 11. The system of claim 10, wherein the mobile water heatingsystem comprises a water reservoir in which water heated to the secondtemperature collects, and the at least one second pump pumps heatedwater from the water reservoir at the second flow rate.
 12. The systemof claim 11, wherein the mobile water heating system comprises aplurality of water heaters each configured to heat a portion of thewater pumped to the mobile water heating system from the firsttemperature to the second temperature and supply the heated water to thewater reservoir.
 13. The system of claim 10, wherein the mobile waterheating system comprises a plurality of water heaters connected togetherin a series, water pumped to the mobile water heating system flowsthrough and is heated by each of the plurality of water heaters; andwater pumped to the mobile water heating system enters a first of theplurality of water heaters at the first temperature and exits a last ofthe plurality of water heaters at the second temperature.
 14. The systemof claim 10, wherein the second temperature is at least 8 degreesFahrenheit greater than the first temperature.
 15. The system of claim10, wherein the first and second flow rates are each at least 100barrels per minute.
 16. The system of claim 10, wherein the secondtemperature is at least 8 degrees Fahrenheit greater than the firsttemperature, and the first and second flow rates are each at least 100barrels per minute.
 17. The system of claim 10, wherein the mobile waterheating system comprises a first truck, and the at least one first pumpis transported by a second truck that is different from the first truck.18. The system of claim 10, wherein the mobile water heating systemcomprises a first truck, the at least one first pump is a first singlepump transported by a second truck that is different from the firsttruck, and the at least one second pump is a second single pumptransported by a third truck that is different from the first and secondtrucks.
 19. The system of claim 10, wherein the mobile water heatingsystem comprises a first truck, and the at least one second pump istransported by a second truck that is different from the first truck.20. A mobile water heating system for use with a water source, at leastone first pump, and at least one second pump, the system comprising: avehicle; and a water heater that is operably attached to the vehicle andmovable therewith as a unit, the water heater comprising: at least onewater inlet couplable to the at least one first pump, the at least onewater inlet being configured to receive water from the at least onefirst pump at a first flow rate of at least 20 barrels per minute; aheating assembly configured to receive water from the at least one waterinlet and heat the water received from the at least one water inlet froma first temperature to a second temperature; and a water reservoircouplable to the at least one second pump, the water reservoir beingconfigured to receive heated water from the heating assembly, and supplythe heated water at a second flow rate of at least 20 barrels per minuteto the at least one second pump.
 21. The mobile water heating system ofclaim 20, wherein the second temperature is at least 8 degreesFahrenheit greater than the first temperature.
 22. The mobile waterheating system of claim 20, wherein the water heater further comprises amanifold and a shell; the shell at least partially defines a firstinternal volume; the manifold is positioned above the water reservoir;the manifold comprises the at least one water inlet and a plurality ofnozzles positioned to spray a first portion of the water received by theat least one water inlet within the first internal volume; the firstportion of the water travels downwardly though the first internal volumeand is received by the water reservoir; the heating assembly comprises aheating coil and a burner; the heating coil is positioned at leastpartially within the first internal volume; the heating coil has a tubecoiled to define a second internal volume; the tube comprises a tubeinlet and a tube outlet; the tube inlet is positioned to receive asecond portion of the water from the manifold; the second portion flowsthrough the coiled tube to the tube outlet; the tube outlet dischargesthe second portion into the water reservoir; and the burner ispositioned to direct flames into the second internal volume to heat thefirst and second portions of the water before the first and secondportions are received by the water reservoir.